New Features in Celestia 1.6.0

Planetshine

In previous versions of Celestia, the only source of illumination was the sun
(or suns, in multiple star systems.) But, light reflected from the surface of
a planet can also be a significant. If you look at images of the International
Space Station, you'll notice that the Earth-facing portion is lit by a bluish
light reflected from the Earth's oceans. Recent images from the Cassini mission
show the moons of Saturn with their Saturn-facing hemispheres illuminated by
the faint glow of Saturnshine. You can now observe these effects in the latest
version of Celestia.

Globular clusters

Globular cluster M5

Much work has been done to add globular clusters to Celestia. Each globular
cluster is drawn realistically in three dimensions using a statistical model
that accounts for such features as overall cluster diameter, the core
diameter, and the distribution of red giants. Brightness across a
globular cluster is modeled by the King profile. The new globular cluster
catalog contains all 150 globular clusters of the Milky Way, with a measured
radius, core radius, and King concentration for each object. The names
assigned to each cluster are compatible with the scheme used in the
SIMBAD astronomical database.

New sky grids

Celestia's sky grid feature has been completely rewritten and greatly
improved. The spacing of lines in the grid will now
adapt to the field of view, making it a much better tool for orienting yourself
at high zoom levels. Coordinate labels are conveniently located at the edges of
the view window. Celestia supports grids for several different coordinate
systems, including equatorial, horizontal (altitude/azimuth), galactic, and
ecliptic.

Updated star catalogs

The main star catalog used in Celestia has been regenerated from an
updated version of the Hipparcos catalog, Floor van Leeuwen's new reduction
of raw data from the Hipparcos mission. The basic catalog has been
supplemented with over 1900 measured stellar radii from the CHARM2 survey,
so a significant fraction of Celestia's stars now have more reliable figures
given for their sizes. The orbits of binary stars were updated, and the
names of stars in multiple systems have been changed to a SIMBAD compatible
syntax. The new extrasolar planet catalog includes the dozens of new worlds
discovered since the last Celestia release.

Selection cursor

A new animated cursor in 1.6.0 makes Celestia easier to use. The animation
effect directs your eye more quickly to the selected item. An arrow at border
of the view window points to the selection when it is offscreen. And, the
cursor changes color when the selection is hidden by a foreground object,
helping you locate the the selection in three dimensions.

Triaxial ellipsoids

Elongated shape of dwarf planet Haumea

While the shapes of most large objects in the solar system are closely
approximated by flattened spheres, there are some exotic worlds that are
noticeably elongated along one axis. The most extreme example of this is
the dwarf planet Haumea (aka 2003 EL 61), which looks more like an American
football than a familiarly spherical planet. Now that Celestia supports
triaxial ellipsoid bodies, you can see the true appearance of such worlds.

Orbit color

Different orbit colors may be assigned for each object in a solar system.
This can help you quickly distinguish the orbits of individual planets. Or,
you can highlight the orbits of a group of related objects.

Dwarf planets

Since 2006, the International Astronomical Union has recognized a new class
of objects called dwarf planets. To date, there are five bodies in our Solar
System that have been assigned dwarf planet status. Version 1.6.0 brings
Celestia up to date with the IAU decision and adds a dwarf planet class. You
can visit all five recognized dwarf planets and their satellites.

New reference marks

Terminator and planetographic grid

Reference marks augment the 3D view with additional information that
can help you understand the locations and relationships between solar system
objects. Celestia 1.6.0 adds a longitude/latitude grid to aid in locating
surface features on planets. Another new reference mark is the terminator, the
boundary between the day and night sides of a world.

Updated Cassini mission

The primary mission of the Cassini spacecraft lasted through mid-2008. In
April 2008, an two-year extended mission was approved. The new version of
Celestia includes the extended mission trajectory, so that you can follow
Cassini around Saturn through 2010. The Huygens probe separation sequence has
been improved using new features in version 1.6.0—watch Huygens
separate smoothly from the main Cassini spacecraft and rendezvous with Titan
three weeks later.

Updated ISS model

New ISS model

The new Celestia package includes a much more detailed model of the
International Space Station, complete with all the modules added through
2008. With the new planetshine feature in 1.6.0, the updated ISS looks
spectacular in low Earth orbit.